JP2002327094A - Colorant, colorant-resin composition and molding thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a molding colored uniformly without deteriorating mechanical properties while suppressing occurrence of white streaks. SOLUTION: This colorant comprises (a) 5 to 80 wt.% of a pigment and (b) 5 to 60 wt.% of an ethylene-vinyl acetate copolymer wax having 1,000 to 10,000 number average molecular weight and containing 5 to 30 wt.% vinyl acetate content.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a colorant and a colorant resin composition for obtaining a colored molded article containing an inorganic filler without generation of white stripes, and a molded article obtained by molding the same.

[0002]

2. Description of the Related Art Molded articles made of a polypropylene-based resin composition containing an inorganic filler have good dimensional stability and impact resistance, and are therefore widely used in applications such as automobile parts and home electric appliances. I have. In general, 5% to 50% of an inorganic filler such as talc, calcium carbonate, mica, glass fiber, etc. is blended with an ethylene propylene block copolymer resin, and if necessary, additives and a coloring agent for the resin are added. , Supplied in compound form.

[0003] However, when a large amount of an inorganic filler is mixed with a non-polar resin such as a polypropylene resin to perform injection molding or extrusion molding, there is a problem that white stripes are generated on the surface of the molded product.

[0004] It is considered that the cause of these is that the inorganic filler accumulates on the cylinder or screw surface in the molding machine or on the outlet of the molding machine to form aggregates, which are separated from the molding machine and migrate to the surface of the molded product. . This phenomenon is caused by increasing the rigidity of the base polypropylene resin,
It becomes even more remarkable as the molding cycle speeds up. Particularly in a colored molded product, there is a problem that the white stripes are conspicuous and the commercial value is significantly reduced.

[0005] In order to prevent such white streaks, a method has been generally proposed in which a compound containing precipitated barium sulfate and silica is blended into a compound for the purpose of removing inorganic filler deposited at the outlet of the molding machine. However, sufficient effect was not obtained.

[0006]

DISCLOSURE OF THE INVENTION The present invention relates to a colored molded article using a polypropylene resin containing an inorganic filler, which suppresses the generation of white streaks without deteriorating the physical properties of the molded article, and which is more uniformly colored. The purpose is to provide.

[0007]

Means for Solving the Problems A first invention of the present invention is:
(A) 5 to 80% by weight of pigment, (b) number average molecular weight of 100
0-10000 and vinyl acetate content 5-30% by weight
5-60% by weight of ethylene vinyl acetate copolymer wax
It is a coloring agent characterized by containing.

[0008] A second invention comprises the colorant described in the first invention, an inorganic filler, and a polypropylene resin.
FR is 5 to 50 g / min. It is a colorant resin composition characterized by these.

A third invention is a molded article obtained by molding the colorant resin composition according to the second invention.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION The pigment (a) which is a component of the colorant of the present invention is a pigment generally used for coloring plastics, for example, azo, phthalocyanine and anthraquinone pigments. , Quinacridone, dioxazine, perylene, indigo, indasulen,
Organic pigments such as quinophthalones, titanium oxide, red iron,
Chromium oxide, graphite, ultramarine, iron black, composite oxide-based inorganic pigments and carbon black, and these are one kind,
Alternatively, two or more kinds can be used in combination.

The amount of the pigment (a) in the colorant is 5 to 5.
It is 80% by weight, preferably 10 to 70% by weight. If the compounding amount is less than 5% by weight, the amount of the coloring agent used increases to achieve the required color, thereby increasing the coloring cost and deteriorating various physical properties of the molded article. Processability deteriorates, and production becomes difficult.

The ethylene-vinyl acetate copolymer wax having a number average molecular weight of 1,000 to 10,000 and a vinyl acetate content of 5 to 30% by weight (hereinafter referred to as EVA wax) is a constituent of the colorant of the present invention. Is not particularly limited, and these partially saponified products may be used. These may be used alone or as a mixture of two or more of those having different number average molecular weights and those having different vinyl acetate contents. When the number average molecular weight of (b) is less than 1,000, various physical properties of the molded article are degraded, and when it is more than 10,000, it becomes a property of a resin, and the effect of suppressing white stripes in the molded article is lost. The number average molecular weight in the present invention is defined as gel permeation chromatography (GP
It is a measured value (polystyrene conversion) in C).

When the vinyl acetate content of (b) is less than 5% by weight, there is no effect of suppressing the generation of white streaks. Lower. Preferably it is 10 to 25% by weight.

The compounding amount of (b) in the coloring agent is 5 to 60.
% By weight. If the amount is less than 5% by weight, the effect of suppressing white streak formation cannot be obtained, and if the amount is more than 60% by weight, the processability during the production of the colorant deteriorates.

The colorant of the present invention may contain (c) a polyolefin wax other than (b).
If the content of (c) is large, the physical properties of the molded article may be reduced, so the amount of (c) in the colorant is preferably 30% by weight or less. Examples of (c) include polyethylene wax, polypropylene wax, modified products thereof, paraffin wax or derivatives thereof such as oxidized modified products, carboxylic acid or carboxylic anhydride modified products, and mixtures thereof.

The colorant of the present invention may contain (d) a polyolefin resin. If the content of (d) is high, the content of pigments and the like is relatively low, and the amount of the coloring agent added increases to achieve the color required for the molded product. The amount of (d) in the coloring agent is preferably 80% by weight or less, since there is a possibility of lowering. (D) may be a homo, block or random polypropylene resin, or a low density, medium density, high density, linear low density polyethylene resin, or a mixture thereof.

The coloring agent of the present invention may contain various additives such as an antioxidant, a weathering stabilizer, an antistatic agent and a lubricant, if necessary.

Examples of the form of the coloring agent of the present invention include flake-like and powder-like dry color, and pellet-like masterbatch. The form can be changed according to a user's request. There is no effect on the streak suppression effect, and there is no difference in any form. When the colorant of the present invention is a dry color, <Method-1> (a) and (b) or (a), (b) and (c) are heated and melted by a kneader such as a kneader or a three-roller. After kneading, it is manufactured by a method of forming a dry color through a pulverizing step. In the case of a master batch, <Method-2> (a) and (b) and (d), or (a) and (b) and (c) and (d), the total amount of which is banbury, kneader,
A method of heating, melt-kneading and granulating with a kneader such as a twin-screw extruder; <Method-3> Dry color and (d), and if necessary, further adding (b), and heating with a single-screw or twin-screw extruder. It is manufactured by a method of melt-kneading and granulating. The above production method is described as an example of the method for producing the colorant of the present invention, and the colorant of the present invention can be obtained by other production methods.

The colorant resin composition (compound) of the present invention contains a colorant, an inorganic filler and a polypropylene resin, and has an MFR (JIS K 7210, a measurement temperature of 230 ° C., a measurement load of 2.16 kg). 5 to 50 g / mi
n. It is. Good molding cannot be achieved with an MFR outside this range.

The content of (a) in the colorant resin composition varies depending on the type of color desired and the shading, etc.
The range of 0.01% by weight to 10% by weight is preferred. Also,
The content of (b) also depends on the type and blending amount of (a).
A range of 2 to 1.5% by weight is preferred.

Examples of the inorganic filler include talc, calcium carbonate, mica, glass fiber and the like. The compounding amount of the inorganic filler in the colorant resin composition (compound) of the present invention is preferably 5 to 50% by weight. Examples of the polypropylene-based resin include an ethylene-propylene block copolymer resin and a resin obtained by adding a rubber component such as ethylene-propylene rubber thereto.

The colorant resin composition of the present invention may be prepared by mixing the above-described colorant, the inorganic filler, and the essential three components of the polypropylene resin at a time, followed by heat-melting and kneading.
Alternatively, a colorant may be mixed with pellets previously kneaded with an inorganic filler and a polypropylene-based resin, and the mixture may be heated and melt-kneaded to produce a colorant resin composition.

The colorant resin composition of the present invention may optionally contain an additive or modifier for the resin. The composition of the colorant resin composition is the same as that of the molded product, and is directly used for injection molding, extrusion molding, and the like. In addition, it is also possible to produce a molded product by mixing a colorant into pellets obtained by kneading an inorganic filler and a polypropylene resin in advance and directly putting the mixture into a molding machine without producing a colorant resin composition. is there. The molded article of the present invention can be used for applications requiring dimensional stability and impact resistance, in addition to automobile parts and home electric appliances.

[0024]

EXAMPLES The present invention will be described in more detail with reference to the following Examples, but it should not be construed that the present invention is limited thereto. Preparation of colorant (dry color, master batch) [Dry color adjustment examples A to F]
Heat melting and kneading were performed using this roll to obtain a flaky dry color.

[0025]

[Table 1]

[Masterbatch Preparation Examples GI] After blending all the ingredients in the composition shown in Table 2 with a Henschel mixer,
The mixture was heated and melt-kneaded by a screw extruder to obtain a pellet-shaped master batch.

[0027]

[Table 2]

Preparation of Colorant Resin Composition (Compound) Example 1 78% by weight of ethylene propylene block copolymer resin (density: 0.90, MFR: 14), talc (average particle diameter D50: 6.5 μm) ) And 2% by weight of Dry Color Preparation Example A were blended in a Henschel mixer in a total amount, and then heated and melted and kneaded with a twin-screw extruder to obtain an inorganic filler-containing colored compound (MFR: 10).

[Examples 2 to 5] 2% by weight of the dry color adjustment example A of the first embodiment was applied to dry color adjustment examples B to
An inorganic filler-containing coloring compound (MFR: 10) was obtained in the same manner as in Example 1 except that E was changed to 2% by weight.

Examples 6 to 8 78% by weight of the ethylene propylene block copolymer resin of Example 1 was added to 77% by weight.
In the same manner as in Example 1, except that 2% by weight of dry color adjustment example A was changed to 3% by weight of master batch adjustment examples G to I, respectively, the coloring compound containing inorganic filler (M
FR: 10) was obtained.

Comparative Example 1 A coloring compound containing an inorganic filler (MFR) was prepared in the same manner as in Example 1 except that 2% by weight of Dry Color Adjustment Example A of Example 1 was changed to 2% by weight of Dry Color Adjustment Example F. : 10) was obtained.

The following evaluation test was conducted using the obtained coloring compound containing an inorganic filler. Table 3 shows the evaluation criteria and the results. White streak evaluation test The inorganic compound-containing coloring compound was molded using an injection molding machine (TOSHIBA MACHINE: IS75E) (molding condition: cylinder temperature / mold temperature: 220 ° C / 40 ° C, residence time 15 minutes) 150 × 120 × A 2 mm plate-shaped product was formed.
After the accumulation, the surface of the molded article was visually observed to confirm the occurrence of white stripes.

Mechanical Property Test (Izod Impact, Heat Deformation Temperature) Using an injection molding machine (manufactured by TOSHIBA MACHINE: IS75E), a colored compound containing an inorganic filler was used (molding condition: cylinder temperature / mold temperature: 220 ° C./40° C.). ) Izod impact and heat deformation temperature test specimens were molded. The test method was performed according to Izod impact JIS 6758 (with a notch) and heating deformation temperature JIS 7207 (load of 0.45 MPa). The evaluation was carried out by adding 80% by weight of a compound containing an inorganic filler containing no coloring agent (ethylene propylene block copolymer resin (density: 0.90, MFR: 14)).
Talc (average particle diameter D50: 6.5 μm) 20% by weight)
Assuming that the numerical value of the test piece obtained in the above step was 100%, the retention rate for this was determined.

[0034]

[Table 3]

[0035]

According to the present invention, when a molded article is manufactured using the coloring agent of the present invention, an inorganic filler, and a colored resin composition containing a polypropylene resin which is a non-polar resin, the inorganic filler is incorporated into a molding machine. Since the adhesion of the aggregates can be suppressed, it is not necessary to interrupt the molding to clean the inside of the molding machine, thereby improving the working efficiency. In addition, since the adhesion of aggregates (the generation of white stripes and the like) to the surface of the molded product can be suppressed, a molded product having excellent appearance can be obtained with uniform quality. Further, since the mechanical properties of the molded article of the present invention are also good, a beautiful molded article can be provided for applications requiring dimensional stability and impact resistance.

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Claims (3)

[Claims] (1) 5 to 80% by weight of a pigment, (b) a number average molecular weight of 1,000 to 10,000 and a vinyl acetate content of 5
5 to 30% by weight of ethylene vinyl acetate copolymer wax 5
A coloring agent, which comprises about 60% by weight. 2. The colorant according to claim 1, and an inorganic filler.
MFR of 5 to 50 g /
min. A colorant resin composition, characterized in that: 3. A molded article obtained by molding the colorant resin composition according to claim 2.